ABSTRACT
Practical analysis of pseudocapacitors by Electrochemical Impedance Spectroscopy (EIS) must consider the effects of porous structures present in some pseudocapacitive materials. Analysis based on EIS allows estimation of frequency behavior, quantification of resistance, and the ability to model equivalent circuits (ECs) of electrochemical supercapacitors (ES) systems. In designing ES devices, asymmetric configuration seems feasible. By carefully analyzing performance characteristics, it is possible to select separate anode and cathode materials that exhibit extended voltage stability and higher capacitance. To increase the capacitance of ESs, some electrochemically active materials are explored for electrode use to provide much higher pseudocapacitance than double-layer capacitance. The most common pseudocapacitance is derived from redox reactions on metal oxide materials and conducting polymers that exhibit a combination of protonation reactions and absorption into the polymer matrix. The chapter focuses on the reversible redox reactions and discuss their fundamental electrochemistry.
